Chuck



v Patented Jan. 14, 1941 UNITED STATES CHUCK." d l Milton L. Benjamin, Cleveland, ohio ApplicafionJuly 29,1939. senat No. 257,392

` 7 Claims. (C1. 2te-*49) This invention relating as indicated to*k achuckv is more'particularly directed to .a collet chuck adapted to grip av tool; bar or similar article.

The general object of the invention isto'pro` vide a collet chuck which 1s expansible a-nd contractible so as to secure a.l tool or the like to a rotatable shaft or arbor.

It is'one-object of the invention to positively eliminate any twisting action between the collet y 10 and -thenose piece` in that type of chuck where axial movement of the nose piece causes -radial movement of the collet member. Heretofore.

in chucks of thisv type thev nose piece'has generally been rotated and this in turn causes twistl5 ing ofthe gripping' collet.

In the presentinvention any tendency` to twist is avoided Asince it is not necessary to rotate the nosevpiece in order to move it axially or longitudinauy. V vIt is anotherobject ofthe invention to' maintain accuratealinem'ent at all times betweenthe nose piece, shan-k' and collet and-'this is accomplished byprovidingv long bearing surfaces upon each of said members. lInv this Way the collet is` maintained irl-accurate alinementoriginally and throughout all of its movements, both radial and/or longitudinal. v AIt is another object of the invention toeliminate screw threaded connections as much as and`it will be seenas the description proceeds that I employ only one pair of screw threads.`

.It is still another object of the invention to provide a novel form odi-.collet member 'which has 3 three cam Vsurfaces or Y pressure seats, thus" in- `suring uniform `radial movement'of the colletv memberas itgrips and releases the tool or the like.

portion of thechuck, it' being a particular object cent suc-h 'vforward portion.

to dispense with screw threads immediately adjad 45 vAnotherob'ject of the invention is toprovide V a chuck of'4 the collet type which is capableof collapsing to a diameter of one-sixteenth of an inch and wherein the interior surface `or bore volvesonly three movements, namely, insertion I 55 of the collet into the bore of the shank, .insertion rotation of a coupling member." I I Lastly, itis an object Vof the invenzion to proflio'weverybut one of various applications of the f principles of my invention.A `In the'accompanying drawing:

Itis a stillffurther object of the'invention to eliminate all complicated mechanism atthe nose ofthe' shankintothe bore of thenose-piecenand vide a chuckwhich is extremely ir'iexpensive' to manufacture as the variousparts canbefmade 5 from ordinary stock and no innovation in 'manufacturing requipment is necessary. n Y

' Tofthe accomplishment of the `foregoing'and related ends, said invention, then, consists of the means hereinafterjfullydescribed andparlo ticularly pointed out in the claims; the annexed l -Idrawing and the following description :setting l forth` in detail certain mechanism'con's'tituting,

Figu is a side elevation'-witnwparts in' section. Fig.' 2 is afvertical `section-taken the line v'iv-a2 orrFig. 1.

tion 33`po'f-Fig'. 1.

Fig.-'4 `isy a perspective viewffofv the collet mem- Referrin'g now to* the drawing and more par-1 'f Fig.` Bis al section taken on'jthe irregularisec-fg ticularly to Fig. `=1,\.it'will be seen that myfchuck 25 comprises a shank member Zi'havin'g a'bore IS at its outer end `within which a collet member lfis slidablyv received.- A nose piece I isslidably received uponthe outer surface of the shank12 and possible-between the collet, shank and nose piece this nose piece 1S provided Wlth'a relatively 10ng`y30 I.

bearing surface 3l adapted to engagethe 'rela-` tively. long. bearing surfacej on lthef-shank so f l that suchv nose piece is held inrpositive :alinez ment at all times. .The shankpis -providedwith an outwardly extending Vshoulder. EI 0- which is f .35 adapted `toengage aninwardly vextending flange I I, on coupling y 3., The -nose piece I is provided with screw threads 'I 2 which engage screwlthreads I3on.the coupling 3 and-assuch'coupling is rovtated,.longitudinal movement is imparted to the nosepiece I. i, y.. The nosepiecel is also provided witha surr)face I4 inthe formzof a hexagonal'lnut so that the same rnaybegripped as the=coupling.is ro# tated. Y f

The collet'member is shown in Fig# andcolm o vprises a relatively long cylindricalor bearing 'surf `face Sand a vrelatively short bearing surface,

ljoining such bearing surfaces.` Oneend GI-of'fthe 50 collet is beveledA atan angle approximately the l same as theangle ofthe camfsurface 1;* The opposite end 8 of-y the colletis `beveled similar: to the beveled or flaring surface I5 inA the: interior onf thenose piece lauslotspzl, 2 2, 23anci' 2 4 eig- V575 tend inwardly from the cam surface! and termitained in accurate alinement regardlessofdts,`

axial position'. Stated inA other words, it may be said that the collet remains accurately alined whether it is totally within the` bore i9 or whether it is positioned outwardly as far as it will travel.

As stated previously, thecam surface or pressure seat 8 engages the cam or pressure surface' I5 on the nose piece l and sirnilarlythe camsursurface 1 on the shank 2 and in additiony the cam surface 6 engages the cam surface IlA on the shank kmember 2. Obviously when this engagement takes place ,tlieY bearingf surfaces Sand ,leave thebearingsurfaces i9 and 3|, respectively. The collet, however, will remain in acvcurate alinementdue to the provision of the Athreefcam surfacesand the collet will contract evenly'throughout its length so that an extremely long, uniform vgripis obtained `upon the tool.

` Akey 32 may be used if is desiredfto positively prohibit rotationalmovementof the nose 'piecei. This key is received in suitable recesses 4in the ,shank 2` and nose piece or, if preferred,v

'maybe made integral with the shank. Thekey and keyways naturallyadd to thecost of; manuy facture and may be omitted if desired.

In operation, a tool is inserted through openingt 2 9 in theforward endy of nosepiece Land it may Aare accurately ground.l

or maynot extend into the bore, i8, of shank 2. The nose piece is then forced to the right as viewedin Fig. .lafter which .the coupling member 3 is rotated, causing ythe longitudinal movementof the nose piece. As the nosepiece l moves to the right the collet is contracted as explained above,l and the toolis securely gripped. .It will. be noted that the collet is not twisted since the. nose piece may be heldby gripping the vhex surface `llas the coupling is rotated. r A

It wiilalso be seen that the collet is maintained in accurate alinement originally as well as throughoutI its total pathof` travel, both radial and/or longitudinal. l -In :additi'onit will beseen that no complicated parts are'present and that the entire devicev may berapidly andLeasilyassembled. Itlis of particulari'mportance to -note that extremely long bear-,

ing surfaces are providedbetweenthe nosefpiece and the shank member thus preventing? radial movementofthe nose piece.' 1"

I It isalso' important to note that the collet member and interior of theshank areprovided with relatively long cooperating bearing surfaces which: aid infmaintaining accurate alinement.

These surfaces however need'not be precisionVv ground 'as are `the bearing 'surfacesonthe shank and nose piece because the conical cam surfaces.

f The long lsurfaces have a further function in wholly devoid of any projecting pieces.

- that all looseness 'is' entirely eliminated andin this connection it should be observed that.l there are` no parts' in my chuck which may be broken off 'or' easily-lost as the'entire mechanismVv is Itv will be riotedthat the three-point suspension of the lcoll'etin'sures constant accuracy whereas Atwo point suspension will not give, constant accuracy.

with additional cam surfaces..

Other modes of applyingthe principle of my invention may be employed instead of the one explained, change being made as regards the means and the steps herein disclosed, provided those stated by any of the following claimsvor their equivalent be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a chuck the combination of a shank member, a nose piece member, a collet member anda coupling member, said 1collet having three axially spaced, conical cam surfaces, said nose piece having one interior, conical cam surface engaging one of said three cam surfaces on said collet, and said shank having two internal coni-V cal cam surfaces engaging the remainingcam surfaces on said collet, the axial distance betweenthe cam surfaces on said shank being substantially equal to the axial distance between said remaining cam surfaces on said collet.

2. Ina chuck the combination of a shank member, a nose piece'member, a collet member and a coupling member, said collet havingthree axially .spaced, conical canrsurfaces, said nose piece having oneinterior, conical cam surface engaging one of said three camsurfaces on said collet, and said shank having two internal conical' .cam'surfaces engaging the remaining cam surfaces on said collet, the conical cam surfaces on said shank member `being substantially rpar- Vallel and spaced Vaxially from each other a disftance that is substantially equal to the axial distance Abetween 'said 'remaining cam surfaces on saidcollet.

3. In a chuck the combination of f a shank member, `anose -piece member, a collet member and a couplingmember, said collet-having three axially spaced, conical cam surfaces, saidnose piece having one interior, conical cam surface engaging one of said three camsurfaces on said collet,

and saidl shank havingV two internal conical cam surfaces engagingthe remaining cam surfaces on said collet, `theconical cam surfaces on said `shank member beingsubstantially parallel andA flaring outwardly from the axis of said chuck, the interior, conical cam surface'onfsaidnose piece flaring in an opposite direction, Athe axialydistance between the cam surfaces on said Ashank being substantially equalnto the axial 'distance between `said remaining cam surfacesv on said collet.

4. In a chuck, a collet having axially spaced cylindrical Lsurfaces and a cam surface, said cam surface joining said spacedcylindrical surfaces,

and both of 'the ends ofsaid cylindrical surfaces,

remote from lsaid cam surface, being provided 5. In a chuck, a collet having" 'axiallyspaced cylindricalsurfaces and a cam surface, said cam surface joining vsaid spaced cylindrical surfaces,

said cylindrical surfaces having different diameters ,-one of said cylindrical surfaces being substantially greater in axial extentthan the other, said collet having radial slotsr ateach end and camsurfaces at'eachend. 6. In a 'chuck the combination of a shank member, a nose piece member,.a collet member tion of said shank member and beingmovableA axially with respect to said shank member upon anda coupling member, said nosepiece member lsurrounding a substantial axially extending poryrotary movementv ofsaid coupling, there being` means present to prevent rotationalfmove'rnent of said nose piecefsuch means including. a key and a keyway, said nose piece extending back- 'surfaces on said shank. the other of which engages a conical cam surface on said nose piece.

, '7. In a chuck, a collet having axially `spaced cylindrical surfaces and a cam surface,lsald cam surface joining said spaced'cylindrical surfaces, vand both ot the ends of said cylindrical surfaces.

remotefrom ysaid cam surface. being provided with additional cam surfaces, one of said`addi tional cam surfaces being parallel throughout its 5 extent to said first named cam surface.

MILTON L. BENJAMIN. 

